The present invention relates to fuel caps for closing filler necks of vehicle fuel tanks. More particularly, the present invention relates to a threaded fuel cap that provides a lost motion driving connection between a handle and a closure member to delay actuation of the closure member in a cap-removal direction following an accidental impact to the handle.
Conventional fuel caps for closing threaded filler necks of vehicle fuel tanks generally include an outer handle or shell that is coupled for rotation to a closure member or housing. The housing is normally formed to include threads that are configured to engage corresponding threads formed on the filler neck. A direct driving connection between the handle and the housing is normally provided. It is known to provide a torque override driving connection between the handle and the housing, however this torque override driving connection is only used to prevent overtightening of the housing within the filler neck. Thus, for all practical purposes, conventional fuel caps for threaded filler necks utilize a fixed, direct driving connection between the handle and the housing which results in coordinated and direct rotational movement of the housing relative to rotational movement of the handle.
One problem with conventional fuel caps of that type is that, because the handle is directly connected to the housing, any unintentional movement of the handle in the cap-removal direction will break the seal between the housing and the filler neck. Once the seal between the housing and the filler neck is broken, it is possible for fuel or fuel vapor to escape from the filler neck. In some instances, such as during a vehicle accident, a release of fuel or fuel vapor can potentially create a hazardous condition.
Threaded fuel caps that engage threads in the filler neck of vehicles are now widely used because of their ease of installation and removal, and because of their excellent sealing characteristics. Therefore, it would be advantageous to provide a fuel cap in which the handle is configured to rotate a predetermined amount in the cap-removal direction without a resulting rotation of the closure or housing to break the seal between the housing and the filler neck. Ideally, when the cap is properly installed, limited unintentional movement of the handle in the cap-removal direction will not interfere with the seal established between the housing and the filler neck. This would be advantageous during a vehicle accident in which the handle of the fuel cap can possibly be rotated due to disruption of the body portion of the vehicle surrounding the fuel cap or to any other external impact.
It is therefore one object of the present invention to provide a fuel cap that provides a lost motion driving connection of a predetermined amount in the cap-removal direction between the handle and the closure to prevent unseating of the seal established between the closure when the handle is rotated unintentionally in the cap-removal direction.
Another object of the present invention is to provide a fuel cap that will provide a direct driving connection between the handle and the closure after the handle has been rotated a predetermined amount in the cap-removal direction to permit the cap to be removed from the filler neck.
Yet another object of the present invention is to provide a fuel cap in which the handle is releasably retained in an orientation that provides the full amount of predetermined lost motion between the handle and the housing when the cap is rotated in the cap-advancing direction to install the cap in the filler neck.
According to the present invention, a cap is provided for use in the filler neck of a fuel tank. The cap includes a closure or housing for closing the filler neck and a handle for rotating the closure relative to the filler neck. The cap also includes a delayed actuation device that is configured to provide a lost motion driving connection between the handle and the closure to permit the handle to rotate through a predetermined angle relative to the closure when the handle is rotated in a cap-removal direction.
One feature of the foregoing structure is that the delayed actuation device is configured to create a lost motion driving connection between the handle and the closure. When the handle is rotated in a cap-removal direction, the handle is permitted to rotate through a predetermined angle relative to the closure before establishing a driving connection therewith to delay breaking the seal between the closure and the filler neck. This feature advantageously aids in increasing the crashworthiness of the fuel cap by lessening the likelihood that the fuel cap will loosen an amount sufficient to break the seal during an accidental impact.
In preferred embodiments of the present invention, the delayed actuation device includes a drive lug coupled to the handle and a pair of driven lugs coupled to the closure. The first driven lug is oriented to engage the drive lug during rotation of the handle in a cap-advancing direction. The second driven lug is located in spaced-apart relation to the first driven lug and is configured to engage the drive lug during rotation of the handle in a cap-removal direction.
One feature of the foregoing structure is that the drive lug coupled to the handle is oriented between two spaced-apart driven lugs coupled to the closure. One advantage of this feature is that the space between the two driven lugs can be selected at the design stage to "program" the predetermined lost motion angle through which the handle and drive lug are permitted to rotate relative to the driven lugs coupled to the closure.
Also in preferred embodiments of the present invention, the delayed actuation device includes a torque-releasable race for selectively disabling a driving connection that is established between the handle and the closure in the cap-advancing direction to permit the handle to rotate relative to the closure through an angle greater than the predetermined angle in response to application of a rotation-inducing torque that is in excess of a predetermined threshold amount.
One feature of the foregoing structure is that the handle is connected for driving engagement to the closure by a torque-releasable race that is configured to permit the handle to rotate relative to the closure in the cap-advancing direction after the closure has been fully engaged in the filler neck in response to a rotation-inducing torque in excess of a predetermined threshold amount. One advantage of this feature is that the torque-releasable race prevents overtightening of the closure within the filler neck.
Also in preferred embodiments of the present invention, the delayed actuation device includes an anti-drift lug that is configured to releasably limit rotation of the handle relative to the race when the closure is installed in the filler neck so that drifting rotation of the handle is substantially blocked in this position.
One feature of the foregoing structure is that the anti-drift lug acts to limit rotation of the handle relative to the race when the cap is installed in the filler neck. One advantage of this feature is that drifting rotation of the handle relative to the race, and consequently relative to the closure, is prevented when the cap is installed in the filler neck. This places the handle in an orientation that advantageously permits the full predetermined angle of lost motion rotation with respect to the closure upon rotation of the handle in the cap-removal direction to prevent premature unseating of the closure from the filler neck.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.